1. Field of the Invention
The present invention, in general relates to electrical connectors and, more particularly, to high current (200-600 amperes) connectors that are intended to rapidly charge the batteries of an electric vehicle (i.e., a vehicle that obtains at least some of its motive power from an electric motor).
As electrically powered and hybrid types of electric and gasoline vehicles continue to grow in design and in popularity, so too does the need to better support these types of vehicles.
Certain of these types of vehicles are driven on the street while others are used in specific areas, such as in airports for the towing of airplanes, baggage, or for other purposes, for example, as fork lifts.
Another group of electrical vehicles that may benefit from rapid recharging is classified, generally, as “Neighborhood Electric Vehicles”. These vehicles, while street legal, are limited to speeds under 30 mph and are becoming increasingly popular for use in retirement communities.
As used throughout this specification, the term “electric vehicle” is intended to include any type of an electrically powered vehicle.
Regardless of where they are used, the need to rapidly recharge the batteries of an electric vehicle exists. As this technology continues to advance, new types of batteries and new types of charging systems are being designed. It is desirable, in general, to be able to charge an electric vehicle as rapidly as possible. Rapid charging minimizes downtime.
Various standards for recharging electric vehicle batteries presently exist and new ones are likely to be developed. For example, according to SAE J1772 “Society of Automotive Engineers Specification”, a “level 3” charge method utilizes 400 amperes maximum charge current and allows a discharged battery to be charged to approximately 80% of its capacity in a short period of time. Clearly, a very large amount of current must be supplied to accomplish recharging within the allotted time frame. (The verbs “charge” and “recharge” or “charging” and “recharging” are used interchangeably herein.)
By way of comparison, a “level 1” rate of charging involves only twelve amperes maximum charge current and requires from six to twelve hours to reach the same battery capacity.
In order to accommodate high current flows, large connectors are used but these then result in high insertion and removal forces which make it difficult for users to connect the charging system plug to the electric vehicle or remove it therefrom.
It has generally been accepted that a hazardous voltage is 48 volts or higher when conditions are dry and 30 volts or higher when conditions are wet.
At airports, electric vehicles operate at from 48 to 150 volts DC. Accordingly, protection from electrical hazard is required for those who handle the electrical connectors that recharge these vehicles.
Also, there are other functions and indications that are desirable on a connector (i.e., a plug) for connection to an electric vehicle but which are currently unavailable. For example, an on/off switch to control operation of the recharging system (i.e., the application of electrical power for recharging the electric vehicle's battery through the connector) is desirable.
As electric vehicle recharging systems grow in sophistication, there may arise a desire to control any of a variety of other functions as well. The use of indicator lights may also be desirable at times and they may used to indicate any condition, such as proper connection of the plug to the mating receptacle, proper or improper rate of charging, power “on” or “off”, etc . . .
Accordingly, there exists today a need for an electric vehicle battery rapid charging connector that has a lower insertion and removal force, incorporates safeguards, and which provides for additional functionality.
2. Description of Prior Art
High current electrical connectors are, in general, known. While the structural arrangements of the above described devices, at first appearance, may have similarities with the present invention, they differ in material respects. These differences, which will be described in more detail hereinafter, are essential for the effective use of the invention and which admit of the advantages that are not available with the prior devices.